The present invention relates generally to material dispensers. Specifically, the present invention relates to a material dispenser including a breaker assembly that prevents the bridging or clogging of a discharge outlet.
Hoppers are well known for their use as material dispensers and in conveying particulate material. Typically, a hopper is a funnel-shaped housing. The hopper has a large opening, or inlet, at the top for receiving the particulate material; and a smaller opening, or outlet, at the bottom for discharging the particulate material. The force of gravity urges the particulate material from the hopper inlet towards the hopper outlet.
Certain particulate materials are prone to form chunks or clumps. These clumps of particulate material can clog or bridge the outlet of the hopper. The clog can reduce or stop the flow of the particulate material from the hopper outlet. The removal of the clumped particulate material from the hopper can prove costly. The flow of particulate material into the hopper inlet must be stopped, and the particulate material present in the hopper must also be removed to access the clumped material.
Numerous attempts have been made to prevent the formation of chunks or clumps in the hopper which can clog or bridge near the hopper outlet. One such attempt is found in U.S. Pat. No. 4,522,500 to Hyer (hereinafter Hyer). Hyer discloses an agitator assembly mounted on the wall of the hopper. The agitator assembly includes a panel disposed within the hopper wall; and a vibrator attached to the external portion of the hopper wall. Both the panel and the vibrator are secured to the hopper wall using elastomeric bushings. The vibrator actuates the panel.
Another attempt is found in U.S. Pat. No. 5,533,650 to Conrad et al. (hereinafter Conrad). Conrad discloses a hopper having both stationary walls and movable walls. Flexible seams connect the opposed movable walls and the opposed stationary walls. A vibration device moves at least one of the movable walls relative to the other movable wall and the stationary walls.
Another attempt involves the use of high pressure air to break up or remove chunks. Air accumulators are provided along the particulate material flow path. The accumulator is valved to selectively inject high pressure air into the material flow path. When a clog occurs, the valve of an accumulator located in that region is opened. The sudden pressure wave produced by the rapid release of the high pressure air enters the particulate material flow path and dislodges the bridge. If detected early enough, the particulate material flow should return to normal.
The aforementioned attempts and other attempts to prevent the formation of chunks or clumps in the hopper which can clog or bridge near the hopper outlet have numerous drawbacks. For instance, the devices may not be capable of sensing the existence of a clog or bridging condition. The devices also may not break up a clog or bridge once it has formed near the hopper outlet. The devices also may not be capable of continued material dispensing operation once a clog or bridge has formed. The devices may not be able to operate in high temperature environments of cement manufacturing plants and other similar processes. Further, the devices may require extensive modification to the hopper for assembly and use.
Clearly, there is room for improvement in the art.